Yeah... people don't realize how censored reddit is because it kind of appears like random free speech. The reality is there are several mechanisms to silence dissent. You can even run a whole sub where it appears that anyone (including you) can post/comment, but only the comments mods approve actually appear. Some websites are explicitly moderated like that, but reddit doesn't claim to be. Most of those websites will also tell you if your comments are approved or not. Reddit is very sneaky just to hide them.

The rate limiting thing is kind of like a ban. It slows down dissent while moderators get around to removing it.